etcd - yumenomatayume

etcd

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etcd

etcd is a strongly consistent, distributed key-value store that provides a reliable way to store data that needs to be accessed by a distributed system or cluster of machines. It gracefully handles leader elections during network partitions and can tolerate machine failure, even in the leader node.

OSS の分散 KVS

Sample

Dockerで試す

etcd用のnetworkの作成

code:bash

docker network create etcd-network --subnet=172.16.0.0/24 --ip-range=172.16.0.0/24

etcdコンテナの作成

code:bash

rm -rf /tmp/etcd-data1.tmp && mkdir -p /tmp/etcd-data1.tmp && \

docker run -d \

--network etcd-network \

--ip 172.16.0.4 \

-p 2379:2379 \

-p 2380:2380 \

--mount type=bind,source=/tmp/etcd-data1.tmp,destination=/etcd-data \

--name etcd1 \

gcr.io/etcd-development/etcd:v3.4.5 \

/usr/local/bin/etcd \

--name etcd1 \

--data-dir /etcd-data \

--listen-client-urls http://0.0.0.0:2379 \

--advertise-client-urls http://0.0.0.0:2379 \

--listen-peer-urls http://172.16.0.4:2380 \

--initial-advertise-peer-urls http://172.16.0.4:2380 \

--initial-cluster etcd1=http://172.16.0.4:2380,etcd2=http://172.16.0.5:2382 \

--initial-cluster-token tkn \

--initial-cluster-state new

rm -rf /tmp/etcd-data2.tmp && mkdir -p /tmp/etcd-data2.tmp && \

docker run -d \

--network etcd-network \

--ip 172.16.0.5 \

-p 2381:2381 \

-p 2382:2382 \

--mount type=bind,source=/tmp/etcd-data2.tmp,destination=/etcd-data \

--name etcd2 \

gcr.io/etcd-development/etcd:v3.4.5 \

/usr/local/bin/etcd \

--name etcd2 \

--data-dir /etcd-data \

--listen-client-urls http://0.0.0.0:2381 \

--advertise-client-urls http://0.0.0.0:2381 \

--listen-peer-urls http://172.16.0.5:2382 \

--initial-advertise-peer-urls http://172.16.0.5:2382 \

--initial-cluster etcd1=http://172.16.0.4:2380,etcd2=http://172.16.0.5:2382 \

--initial-cluster-token tkn \

--initial-cluster-state new

etcdコンテナの確認

code:bash

$ docker container ls

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

c5d576185df4 gcr.io/etcd-development/etcd:v3.4.5 "/usr/local/bin/etcd…" 3 minutes ago Up 3 minutes 2379-2380/tcp, 0.0.0.0:2381-2382->2381-2382/tcp etcd2

dbf2bff87e48 gcr.io/etcd-development/etcd:v3.4.5 "/usr/local/bin/etcd…" 4 minutes ago Up 4 minutes 0.0.0.0:2379-2380->2379-2380/tcp etcd1

データ投入と確認

code:bash

curl -X POST -d '{"key": "hoge","value": "fuga"}' http://localhost:2379/v3/kv/put

# 両方で追加されていることを確認

curl -L http://localhost:2379/v3/kv/range -X POST -d '{"key": "hoge"}'

curl -L http://localhost:2381/v3/kv/range -X POST -d '{"key": "hoge"}'

backup

code: (bash)

ETCDCTL_API=3 etcdctl \

--endpoints=https://127.0.0.1:2379 \

--cert=/etc/kubernetes/pki/etcd/ca.crt \

--cacert=/etc/kubernetes/pki/etcd/server.crt \

--key=/etc/kubernetes/pki/etcd/ca.key \

snapshot save /opt/snapshot-pre-boot.db

restore

code: (bash)

ETCDCTL_API=3 etcdctl \

--endpoints=https://[127.0.0.1]:2379 \

--cert=/etc/kubernetes/pki/etcd/server.crt \

--cacert=/etc/kubernetes/pki/etcd/ca.crt \

--key=/etc/kubernetes/pki/etcd/server.key \

--name=master \

--data-dir /var/lib/etcd-from-backup \

--initial-cluster=master=https://127.0.0.1:2380 \

--initial-cluster-token etcd-cluster-1 \

--initial-advertise-peer-urls=https://127.0.0.1:2380 \

snapshot restore /opt/snapshot-pre-boot.db

code: /etc/kubernetes/manifests/etcd.yaml

volumes:

- hostPath:

path: /var/lib/etcd-from-backup

type: DirectoryOrCreate

name: etcd-data

Reference

分散KVS「etcd」の環境を世界最速で構築！！ | SIOS Tech. Lab

kubernetes内のetcdをバックアップ・リストアする - goodbyegangsterのブログ